domain | status | count --------------------------------------+-------------------------+-------- academic.oup.com | | 1243 academic.oup.com | spn2-cdx-lookup-failure | 990 aip.scitation.org | | 313 aip.scitation.org | spn2-cdx-lookup-failure | 224 ajps.uomustansiriyah.edu.iq | | 235 apps.crossref.org | | 1329 apps.crossref.org | spn2-cdx-lookup-failure | 942 apps.crossref.org | no-pdf-link | 387 archaeologydataservice.ac.uk | | 422 archaeologydataservice.ac.uk | spn2-cdx-lookup-failure | 289 arxiv.org | | 3512 arxiv.org | spn2-cdx-lookup-failure | 2319 arxiv.org | success | 1177 assets.researchsquare.com | | 571 assets.researchsquare.com | spn2-cdx-lookup-failure | 322 assets.researchsquare.com | success | 249 brill.com | | 397 brill.com | spn2-cdx-lookup-failure | 265 cla.berkeley.edu | | 239 classiques-garnier.com | | 249 cyberleninka.ru | | 340 cyberleninka.ru | spn2-cdx-lookup-failure | 244 dergipark.org.tr | | 468 dergipark.org.tr | spn2-cdx-lookup-failure | 333 dl.acm.org | | 592 dl.acm.org | spn2-cdx-lookup-failure | 470 doi.ala.org.au | | 288 doi.ala.org.au | spn2-cdx-lookup-failure | 220 doi.org | | 1107 doi.org | terminal-bad-status | 679 doi.org | spn2-cdx-lookup-failure | 415 downloads.hindawi.com | | 279 downloads.hindawi.com | success | 267 edbs.uomustansiriyah.edu.iq | | 294 edbs.uomustansiriyah.edu.iq | spn2-cdx-lookup-failure | 209 elibrary.kdpu.edu.ua | | 320 elibrary.kdpu.edu.ua | spn2-cdx-lookup-failure | 233 elibrary.ru | | 722 elibrary.ru | spn2-cdx-lookup-failure | 505 europepmc.org | | 986 europepmc.org | spn2-cdx-lookup-failure | 681 europepmc.org | success | 291 figshare.com | | 377 figshare.com | spn2-cdx-lookup-failure | 328 fjfsdata01prod.blob.core.windows.net | | 255 fjfsdata01prod.blob.core.windows.net | spn2-cdx-lookup-failure | 216 hammer.purdue.edu | | 224 ieeexplore.ieee.org | | 3904 ieeexplore.ieee.org | spn2-cdx-lookup-failure | 2654 ieeexplore.ieee.org | gateway-timeout | 792 ieeexplore.ieee.org | spn2-backoff | 419 journals.eco-vector.com | | 428 journals.eco-vector.com | spn2-cdx-lookup-failure | 306 journals.lww.com | | 727 journals.lww.com | spn2-cdx-lookup-failure | 622 journals.openedition.org | | 806 journals.openedition.org | spn2-cdx-lookup-failure | 554 journals.plos.org | | 348 journals.plos.org | spn2-cdx-lookup-failure | 244 kiss.kstudy.com | | 226 kluwerlawonline.com | | 723 kluwerlawonline.com | spn2-cdx-lookup-failure | 489 kluwerlawonline.com | link-loop | 203 linkinghub.elsevier.com | | 401 linkinghub.elsevier.com | spn2-backoff | 342 mdpi-res.com | | 1463 mdpi-res.com | success | 1337 muse.jhu.edu | | 346 muse.jhu.edu | spn2-cdx-lookup-failure | 253 onepetro.org | | 363 onepetro.org | spn2-cdx-lookup-failure | 284 online.ucpress.edu | | 1620 online.ucpress.edu | spn2-cdx-lookup-failure | 1511 onlinelibrary.wiley.com | | 2913 onlinelibrary.wiley.com | spn2-cdx-lookup-failure | 2109 onlinelibrary.wiley.com | terminal-bad-status | 787 opendata.uni-halle.de | | 519 opendata.uni-halle.de | spn2-cdx-lookup-failure | 343 osf.io | | 1554 osf.io | spn2-cdx-lookup-failure | 1350 papers.ssrn.com | | 2207 papers.ssrn.com | spn2-cdx-lookup-failure | 1727 papers.ssrn.com | link-loop | 457 psycharchives.org | | 384 psycharchives.org | spn2-cdx-lookup-failure | 283 publons.com | | 493 publons.com | spn2-cdx-lookup-failure | 348 pubs.acs.org | | 1240 pubs.acs.org | spn2-cdx-lookup-failure | 881 pubs.acs.org | terminal-bad-status | 298 pubs.rsc.org | | 603 pubs.rsc.org | spn2-cdx-lookup-failure | 460 repositories.lib.utexas.edu | | 1861 repositories.lib.utexas.edu | spn2-cdx-lookup-failure | 1288 repositories.lib.utexas.edu | terminal-bad-status | 523 s3-eu-west-1.amazonaws.com | | 216 sage.figshare.com | | 374 sage.figshare.com | spn2-cdx-lookup-failure | 309 scholar.dkyobobook.co.kr | | 220 scholarworks.gsu.edu | | 749 scholarworks.gsu.edu | spn2-cdx-lookup-failure | 577 tandf.figshare.com | | 214 www.atlantis-press.com | | 338 www.atlantis-press.com | spn2-cdx-lookup-failure | 214 www.cairn.info | | 782 www.cairn.info | spn2-cdx-lookup-failure | 541 www.cambridge.org | | 2325 www.cambridge.org | spn2-cdx-lookup-failure | 1787 www.cambridge.org | no-pdf-link | 300 www.cell.com | | 213 www.concrete.org | | 476 www.concrete.org | spn2-cdx-lookup-failure | 340 www.dbpia.co.kr | | 375 www.dbpia.co.kr | spn2-cdx-lookup-failure | 275 www.degruyter.com | | 3849 www.degruyter.com | spn2-cdx-lookup-failure | 2969 www.degruyter.com | no-pdf-link | 712 www.dib.ie | | 1100 www.dib.ie | spn2-cdx-lookup-failure | 1038 www.e-periodica.ch | | 821 www.e-periodica.ch | spn2-cdx-lookup-failure | 620 www.e-periodica.ch | no-pdf-link | 201 www.elibrary.ru | | 401 www.elibrary.ru | spn2-cdx-lookup-failure | 281 www.emerald.com | | 390 www.emerald.com | spn2-cdx-lookup-failure | 275 www.eurekaselect.com | | 275 www.frontiersin.org | | 1266 www.frontiersin.org | spn2-cdx-lookup-failure | 1025 www.hanspub.org | | 229 www.hindawi.com | | 604 www.hindawi.com | spn2-cdx-lookup-failure | 594 www.inderscience.com | | 201 www.jstage.jst.go.jp | | 1094 www.jstage.jst.go.jp | spn2-cdx-lookup-failure | 807 www.jstage.jst.go.jp | success | 206 www.mdpi.com | | 4340 www.mdpi.com | spn2-cdx-lookup-failure | 4258 www.nomos-elibrary.de | | 2749 www.nomos-elibrary.de | spn2-cdx-lookup-failure | 1909 www.nomos-elibrary.de | redirect-loop | 819 www.osti.gov | | 275 www.oxfordhandbooks.com | | 248 www.oxfordhandbooks.com | spn2-cdx-lookup-failure | 224 www.pdcnet.org | | 217 www.researchsquare.com | | 483 www.researchsquare.com | spn2-cdx-lookup-failure | 317 www.scielo.br | | 319 www.scielo.br | spn2-cdx-lookup-failure | 222 www.sciencedirect.com | | 3384 www.sciencedirect.com | spn2-cdx-lookup-failure | 3267 www.spiedigitallibrary.org | | 441 www.spiedigitallibrary.org | spn2-cdx-lookup-failure | 327 www.tandfonline.com | | 2401 www.tandfonline.com | spn2-cdx-lookup-failure | 1552 www.tandfonline.com | no-pdf-link | 303 www.tandfonline.com | blocked-cookie | 250 www.taylorfrancis.com | | 1232 www.taylorfrancis.com | spn2-cdx-lookup-failure | 908 www.thieme-connect.de | | 520 www.thieme-connect.de | spn2-cdx-lookup-failure | 366 www.worldscientific.com | | 383 www.worldscientific.com | spn2-cdx-lookup-failure | 276 zenodo.org | | 10625 zenodo.org | spn2-cdx-lookup-failure | 7777 zenodo.org | success | 1574 zenodo.org | no-pdf-link | 1160 zivahub.uct.ac.za | | 3428 zivahub.uct.ac.za | spn2-cdx-lookup-failure | 2845 zivahub.uct.ac.za | no-pdf-link | 583 | | 130491 | spn2-cdx-lookup-failure | 95169 | success | 13354 | no-pdf-link | 9621 | terminal-bad-status | 3385 | spn2-backoff | 2396 | redirect-loop | 2216 | link-loop | 1850 | gateway-timeout | 1061 | spn2-error:blocked-url | 428 | blocked-cookie | 415 | spn2-error | 246 (182 rows) ---- The overwhelming thing is `spn2-cdx-lookup-failure`. Should check in after a week or two, when crawling and retries are running smoothly, and see what things look like then.